Keycloak is designed to cover most use-cases without requiring custom code, but we also want it to be customizable. To achive this Keycloak has a number of SPIs which you can implement your own providers for.

To implement an SPI you need to implement it's ProviderFactory and Provider interfaces. You also need to create a provider-configuration file. For example to implement the Event Listener SPI you need to implement EventListenerProviderFactory and EventListenerProvider and also provide the file META-INF/services/org.keycloak.events.EventListenerProviderFactory For example to implement the Event Listener SPI you start by implementing EventListenerProviderFactory: events; public String getId() { return "my-event-listener"; } public void init(Config.Scope config) { int max = config.getInt("max"); events = new MaxList(max); } public EventListenerProvider create(KeycloakSession session) { return new MyEventListenerProvider(events); } public void close() { events = null; } } }]]> The example uses a MaxList which has a maximum size and is concurrency safe. When the maximum size is reached and new entries are added the oldest entry is removed. Keycloak creates a single instance of EventListenerProviderFactory which makes it possible to store state for multiple requests. EventListenerProvider instances are created by calling create on the factory for each requests so these should be light-weight. Next you would implement EventListenerProvider: events; public MyEventListenerProvider(List events) { this.events = events; } @Override public void onEvent(Event event) { events.add(event); } @Override public void close() { } } }]]> The file META-INF/services/org.keycloak.events.EventListenerProviderFactory should contain the full name of your ProviderFactory implementation:

Keycloak loads provider implementations from the file-system. By default all JARs inside standalone/configuration/providers are loaded. This is simple, but requires all providers to share the same library. All provides also inherit all classes from the Keycloak class-loader. In the future we'll add support to load providers from modules, which allows better control of class isolation. To register your provider simply copy the JAR including the ProviderFactory and Provider classes and the provider configuration file to standalone/configuration/providers. You can also define multiple provider class-path if you want to create isolated class-loaders. To do this edit keycloak-server.json and add more classpath entries to the providers array. For example: The above example will create two separate class-loaders for providers. The classpath entries follow the same syntax as Java classpath, with ';' separating multiple-entries. Wildcard is also supported allowing loading all jars (files with .jar or .JAR extension) in a folder, for example:

Here's a list of the available SPIs and a brief description. For more details on each SPI refer to individual sections. Account Provides the account manage console pages. The default implementation uses FreeMarker templates. Connections Infinispan Loads and configures Infinispan connections. The default implementation can load connections from the Infinispan subsystem, or alternatively can be manually configured in keycloak-server.json. Connections Jpa Loads and configures Infinispan connections. The default implementation can load datasources from WildFly/EAP, or alternatively can be manually configured in keycloak-server.json. Connections Jpa Updater Updates database schema. The default implementation uses Liquibase. Connections Mongo Loads and configures MongoDB connections. The default implementation is configured in keycloak-server.json. Email Formats and sends email. The default implementation uses FreeMarker templates and JavaMail. Events Listener Listen to user related events for example user login success and failures. Keycloak provides two implementations out of box. One that logs events to the server log and another that can send email notifications to users on certain events. Events Store Store user related events so they can be viewed through the admin console and account management console. Keycloak provides implementations for Relational Databases and MongoDB. Export Exports the Keycloak database. Keycloak provides implementations that export to JSON files either as a single file, multiple file in a directory or a encrypted ZIP archive. Import Imports and exported Keycloak database. Keycloak provides implementations that import from JSON files either as a single file, multiple file in a directory or a encrypted ZIP archive. Login Provides the login pages. The default implementation uses FreeMarker templates. Login Protocol Provides protocols. Keycloak provides implementations of OpenID Connect and SAML 2.0. Realm Provides realm and application meta-data. Keycloak provides implementations for Relational Databases and MongoDB. Realm Cache Caches realm and application meta-data to improve performance. Keycloak provides a basic in-memory cache and a Infinispan cache. Theme Allows creating themes to customize look and feel. Keycloak provides implementations that can load themes from the file-system or classpath. Timer Executes scheduled tasks. Keycloak provides a basic implementation based on java.util.Timer. User Provides users and role-mappings. Keycloak provides implementations for Relational Databases and MongoDB. User Cache Caches users and role-mappings to improve performance. Keycloak provides a basic in-memory cache and a Infinispan cache. User Federation Support syncing users from an external source. Keycloak provides implementations for LDAP and Active Directory. User Sessions Provides users session information. Keycloak provides implementations for basic in-memory, Infinispan, Relational Databases and MongoDB